Heat pipe with unequal cross-sections

ABSTRACT

The heat pipe of the invention includes an evaporation section and two condensation sections. The evaporation section is located at a part of the heat pipe. The two condensation sections are separately located at two opposite sides of the evaporation section. The evaporation section and the two condensation sections communicate with each other, and a peripheral size of the evaporation section is larger than that of each of the condensation sections.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to heat pipes, particularly to heat pipes with unequal cross-sections.

2. Related Art

Modern electronic components generate more and more heat than ever. Heat pipes can rapidly transfer a large amount of heat. Conventional heat sinks without heat pipes are unable to effectively dissipate heat from modern electronic components. Thus heat sinks associated with heat pipes has become a mainstream.

A conventional heat pipe is composed of an even tube, a capillary structure and a working fluid. The wick is disposed in the tube and abuts against the inner side thereof. The working fluid is contained in the capillary structure.

However, the even tube with equal cross-section cannot be accelerated to transfer heat when the working fluid is evaporated into vapor. Thus its efficiency of heat transfer is limited. On the other hand, the even tube cannot be bent in a smaller radius of curvature because of its equal cross-section. Hence, the tube may not be formed into a desired shape.

SUMMARY OF THE INVENTION

An object of the invention is to provide a heat pipe which has multiple sections with different cross-sections to accelerate flowing speed of vapor and to enhance efficiency of heat transfer.

Another object of the invention is to provide a heat pipe which can be bent in a smaller radius of curvature.

To accomplish the above object, the heat pipe of the invention includes an evaporation section and two condensation sections. The evaporation section is located at a part of the heat pipe. The two condensation sections are separately located at two opposite sides of the evaporation section. The evaporation section and the two condensation sections communicate with each other, and a peripheral size of the evaporation section is larger than that of each of the condensation sections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the invention;

FIG. 2 is a longitudinal section view of the invention;

FIG. 3 is a cross section view along the line 3-3 in FIG. 2;

FIG. 4 is a perspective view of the invention;

FIG. 5 is a longitudinal section view of the invention;

FIG. 6 is a perspective view of another embodiment of the invention;

FIG. 7 is a longitudinal section view of the embodiment shown in FIG. 6;

FIG. 8 is a cross section view along the line 8-8 in FIG. 7;

FIG. 9 is a cross section view along the line 9-9 in FIG. 7;

FIG. 10 is a schematic view of the invention associated with a heat sink;

FIG. 11 is a schematic view of the invention associated with another heat sink; and

FIG. 12 is a cross section view of the evaporation section of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Please refer to FIGS. 1-5. The invention provides a heat pipe with unequal cross-sections. The heat pipe may be a metallic tube. The heat pipe 1 includes a tube 10, a first capillary structure 20, a second capillary structure 30, a working fluid 40, an evaporation section 101 and two condensation sections 102, 103.

The tube 10 is made of copper or copper alloy with great thermo-conductivity. The tube 10 may be a straight tube with a circular cross-section and has a chamber 11 therein. The inner wall of the tube 10 is formed with a plurality of grooves 12. And a protrusion 13 is formed between two adjacent grooves 12. The grooves 12 and protrusions 13 constitute the first capillary structure 20 as shown in FIG. 3.

The middle portion of the tube 10 is expanded by a flaring process such that the chamber 11 a at the middle portion is larger than the chamber 11 b at two opposite ends in size. Similarly, this shape of the tube 10 may be formed by shrinking two opposite ends of the tube 10.

Preferably, the second capillary structure 30 formed by metal powder, mesh net or fiber bundle may be disposed on the inner wall of the tube 10. In other words, there are the first capillary structure 20 and second capillary structure 30 in chamber 11 b of the tube 10.

The middle portion of the tube 10 functions as the evaporation section 101 for contacting a heat source (not shown). The two opposite ends of the tube 10 function as the two condensation sections 102, 103 for connecting a fin set. The condensation sections 102, 103 and the evaporation section 101 communicate with each other. And the evaporation section 101 is larger than each of the condensation sections 102, 103 in size.

FIGS. 6-9 show another embodiment of the heat pipe 1′ of the invention. This embodiment differs from the above by the tube 10 being a straight tube with a flat cross-section. Similarly, the evaporation section 101 is larger than each of the condensation sections 102, 103 in size. The evaporation section 101 is disposed with the first capillary structure 20 formed by the grooves 12 and protrusions 13 and the condensation sections 102, 103 are disposed with the first capillary structure 20 and the second capillary structure 30 formed by metal powder, mesh net or fiber bundle.

FIGS. 8 and 9 show that the area of cross-section of the chamber 11 a is larger than that of the chamber 11 b. As a result, when the working fluid 40 is evaporated into vapor, the vapor can be accelerated in flowing speed. Besides, the flat shape of the heat pipe 1′ may enlarge the area of thermal contact to further enhance the efficiency of heat transfer.

FIG. 10 shows that the heat pipe of the invention is used in a heat sink. The heat sink includes the heat pipe 1′, fin sets 5 and two fans 6. The condensation sections 102, 103 bendingly extend from the evaporation section 101. The condensation sections 102, 103 are disposed with the fin sets 5 and the fans 6 are separately fixed on the fin sets 5. Because the condensation sections 102, 103 are smaller than the evaporation section 101 in size, the condensation sections 102, 103 may be bent in a smaller radius of curvature to decrease the overall volume of a heat sink. Furthermore, the larger evaporation section 101 can make a bigger area of thermal contact with a heat source to enhance efficiency of heat transfer.

FIG. 11 shows another heat sink with the heat pipe of the invention. In this embodiment, the two condensation sections 102, 103 are perpendicularly bent twice to form a substantially ringed shape such that the overlapped condensation sections 102, 103 pass through the same fin set 5.

Besides, the evaporation section 101 and the condensation sections 102, 103 may be formed into a circular shape and a flat shape, respectively. The evaporation section 101 and the condensation sections 102, 103 may be formed into a flat shape and a circular shape, respectively. The evaporation section 101 and the condensation sections 102, 103 may be formed into a semicircular shape as shown in FIG. 12 and a circular shape, respectively. The evaporation section 101 and the condensation sections 102, 103 may be formed into a semicircular shape as shown in FIG. 12 and a flat shape, respectively.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the invention as defined by the appended claims. 

1. A heat pipe comprising: an evaporation section located at a part of the heat pipe; and two condensation sections separately located at two opposite sides of the evaporation section; wherein the evaporation section and the two condensation sections communicate with each other, and a peripheral size of the evaporation section is larger than that of each of the condensation sections.
 2. The heat pipe of claim 1, wherein the heat pipe is made of metal.
 3. The heat pipe of claim 1, wherein the heat pipe is a straight tube with a circular cross-section.
 4. The heat pipe of claim 1, wherein the heat pipe is a straight tube with a flat cross-section.
 5. The heat pipe of claim 1, wherein the evaporation section is circular, semicircular or flat in shape.
 6. The heat pipe of claim 5, wherein each of the condensation sections is circular or flat in shape.
 7. The heat pipe of claim 1, further comprising a first capillary structure disposed in the evaporation section and the condensation sections.
 8. The heat pipe of claim 7, further comprising a second capillary structure disposed in each of the condensation sections and covering the first capillary structure.
 9. The heat pipe of claim 8, further comprising a working fluid filled in the heat pipe.
 10. A heat sink comprising: a heat pipe comprising: an evaporation section located at a part of the heat pipe; and two condensation sections separately located at and bendingly extending from two opposite sides of the evaporation section; wherein the evaporation section and the two condensation sections communicate with each other, and a peripheral size of the evaporation section is larger than that of each of the condensation sections; and a fin set disposed on at least one of the condensation sections.
 11. The heat sink of claim 10, wherein the heat pipe is made of metal.
 12. The heat sink of claim 10, wherein the heat pipe is a straight tube with a circular cross-section.
 13. The heat sink of claim 10, wherein the heat pipe is a straight tube with a flat cross-section.
 14. The heat sink of claim 10, wherein the evaporation section is circular, semicircular or flat in shape.
 15. The heat sink of claim 14, wherein each of the condensation sections is circular or flat in shape.
 16. The heat sink of claim 10, further comprising a first capillary structure disposed in the evaporation section and the condensation sections.
 17. The heat sink of claim 16, further comprising a second capillary structure disposed in each of the condensation sections and covering the first capillary structure.
 18. The heat sink of claim 17, further comprising a working fluid filled in the heat pipe.
 19. The heat sink of claim 10, further comprising a fan disposed on one side of the fin set. 